Underfeed stoker



6 Sheets-Sheet 1 INVENTOR. Edd/and Earl M ATTORNEY.

May 4,1926. "1,583,144

' E. J. HART UNDERFEED sToKER Fi1ed 0ct. 1,9; 1921 .6 Sheets-Shet 4 I N V EN TOR.

' I ATTORNEY.-

May 4,1926. 1,583,144

I E. J. HART UNDERFEED S TOKER Filed Oct. 19, 1921 6 Sheets-Sheet 5 I N TEN TOR Edwarfi cl- May 4 1926. 1,583,144

- E. J. HART' U NDERFEED STOKER Filed Opt. 19, 1921 6 Sheets-Sheet 6 INVENTOR.

ATTORNEY.

Patented May 4, 1926.

UNITED STATES EDWARD J. HART, F. PHILADELPHIA, PENNSYLVANIA.

UNDEBFEED SIO'KER.

Application filed October 19, 1921. Serial No. 508,648.

T 0 aZZ 107mm it may concern Be it known that I, EDWARDJ. HART, ,a citizen of the United States, residing at Philadelphia, in the county of Philadelphia and State of Pennsylvania, have invented new and useful Improvements in an Underfeed Stoker, of which the following .is a speciii ation.

My invention relates'to new and useful improvements in underfeed stokers, and has for its object to provide a plurality of pushing heads located in spaced relation to each other along one or more edges of the grate, as a whole, for positively forcing the fuel over the grate longitudinally of the grate bars.

Another object of this invent-ion is to construct the pushing heads separate from the grate bars and provide means to actuate them for forcing the fuel over the grate bars.

Another object of the invention is to produce a pushing head with an extension to be also used as a pusher'where extra long grate bars are utilized.

A still further object of the invention is to provide a unique means for actuatingthe pushing heads and other coacting movable elements from the mechanism propelling the fuel injecting ram and fuel pushers in the retort.

lVith these ends in view, this invention consists in the details'of construction and combination of elements hereinafter set forth and then specifically designated by the claims.

In order that those skilled in the art to which this invention appertains, may understand how to make and use the same, I will describe its construction in detail, referring by numerals to the accompanying drawings forming a part of this application, in which Fig. 1, is a fragmentary'plan View of theinterior of a furnace embodying my invention and illustrating the relation thereto, of the feeding mechanism and hopper, the latter being on the exterior of the furnace.

Fig. 2, is an enlarged sectional view ape proximately on the line 2 2 of Fig. l.

si n n r ed t ans erse s t o view of the interior constructions at approximately the line 3. 3 of Fig. 1, some of the parts being left in elevation.

Fig. 41, is a fragmentary detail view si ni-r t s- 3 illu ra ng the c iistin ti a f th d mping grate ments ing rod of the rocking bars Fig. .5, is a fragmentary view illustrating a pushing head with an extension, the stationary imperforate. grate bar being shown in section. v

Fig. 6, is. a fragmentary horizontal sectional view through the partitions or walls of the a r box above the dampers to illustrate the means of operating said dampers.

.Figzti, is an enlarged fragmentary sectional View of the valve mechanism controlling the movable elements of the stoker.

' Fig. 8, is a plan view of a portion thereof illustrating its relation to the valve actuating mechanism.

Fig. 9, is an enlarged fragmentary plan view of the adjustable means for transmitting. motion from the pusher to the connect- Fig. 10, is a front elevation thereof with the pusher removed while parts of the grate bars and retort and opposite pushing heads are shown to illustrate the relation of the different elements; Fig. 11 is a fragmentary view part-1y i elevation and partly in section. to show the relation between the valve mechanism and the means by which motion is transmitted to the different movable parts. I

In carrying out my invention as here embodied, 2 represents a furnace the walls of which may be of any suitable construction and within thisfurnace is'located a longitudinal retort 3 preferably centrally arranged and located belowthe grate surface.

The retort 3 is located above an air box 4 which communicates with air chambers 5 by means of openings 6 which are controlled by the dampers or wind grates 7 arranged in pairs opposite each other and each of said dampers or wind gates is connected by a rod 8 with an oscillating member 9 suitably pivoted to a depending member connected with the retort. All of the oscillating members ,9 are connected byan operating rod 10 whereby all'of the oscillating'members may be simultaneously actuated for opening or closing the wind gates. Thev operation of the wind gates will be obvious upon reference to Fig. 6 The air chambers 5 are directly below the grates consisting of the imperf0- rate grate bars ll and the perforate. gratev bars12. As'slio wn in Fig. 8 the perforate grate bars are movable longitudinally and e area he unp feds eithe -s a 3 and the outer partitions 13.

of grate barslQ is constructed in the form of steps, each step hav ing two side walls converging toward each other terminating in an apex and in these side walls are 7 located the draught outlets 14; also each of these grates has a hollow head 15 throughwhich the draught openings 16 are formed and between these perforate grate bars 12 are lo- (rated the imperforate grate bars 11 the same having lugs 1? to engage on both sides of the outer partitions 13 on which the outer ends of the imperforate bars 11 rest. The inner ends of the grate bars 11 rest in the recesses 18 formed in the pushing heads 19. Each of said pushing heads' has a pushing face or surface 20 above its respective grate bar and also has spaced lugs 21 which engage the web 22 of the rocker shaft 23 and likewise the perforate grate bars 12 are provided with spaced lugs 2a which also engagethe web of the rocker shaft As there are two sets of grate bars one on each side of the retort two rocker shafts are shown and all of the grate bars are inclined towards their outer ends, as plainly shown inFig. 3. V

From the foregoing description it will be noted that as the rocker shafts are oscillated the perforate grate bars 12 and the pushing heads 19 will be reciprocated so as to gradually force the fire bed fuel outwardly along the grate bars and during this iine the desired amount of air is permitted to flow through the perforate grate bars and through the draught openings in the hollow heads formed *ith said grate bars.

As the tire bed is moved forward it will finally be moved on to the sectional dump grates 25 one of which is located at each side of the furnace below the lowermost ends of the grate bars and all of the sections 26 of each dump grate are fastened together by means of an-angle iron 27 or its equivalent secured to the sections by bolts 28, said sections also being fastened to a dumping bar 29.

The dumping bar is preferably rectangular in cross section, as shown in Fig. 1, while each section of the dumping grate is formed of two parts securely held about a dumping bar by means of a bolt 30.

T he dumping grates are located above the ash pits S1 to which lead. air conduits 32 from the air box 4:, said conduits being controlled by dampers 33 here shown as but terfly valves, actuated in any suitable .well known manner so that should any unburned fuel happen to reach the dump grates a sufficient amount of air may be supplied thereto to cause the same to be entirely burned before entering the ash pits.

'I he fuel is fed from a hopper 3-1 located, on theoutside of the furnace, by a ram 35, Op r tive the hreat 3 nto the retort 3 along which it isinoved by the pushers 3?. The ram as shown is a hollow box like member'formed of two interlocking parts held together by a pin 36 or its equivalent and this ram is connected to an extension 37 of the slide 38 attached to the piston rod 39 of the piston it) sliding in the cylinder 4-1. To the slide is attached the pusher rod -12 to which all of the pushers 37 are fixed.

The movements of the piston it) cause the pushers 3'? and the ram to be reciprocated for n'ioving the fuel so that the same will gradually pile up within the retort and run over on to the grate bars where it will be moved forwardby the pushing heads and the reciprocating grate bars 12 and in order to prevent the fuel becoming choked in the smaller lower end of the hopper I provide an agitator which consists of two bars as. f pivoted to each other as at d6 with one also pivoted to the ram as at 47 and the other to some suitable part of the hopper as at 48 the movements of the ram causing the parts of the agitator to be drawn across the mouth of the hopper and at times causing it to be moved partly out of and into said hopper thereby effectually looseningor breaking up any fuel which may have a tendency to clog in the smaller end of said hopper.

' On the slide 38 is pivoted a yoke by means of an integral trunnion 50 formed with said yoke and set in a suitable recess in the slide and one end of said yoke is re cesscd in a blocl: 51' having threaded connection with an adjusting screw 52 swivellcd in any suitable manner in the side walls or projections formed with the slide 38 and said screw has means 5 here shown as a hand wheel, mounted thereon for revolving the screw to move the blocks 51 transversely of the slide whereby the pitch of the yoke is changed as desired.

god to function within the yoke is a roller on the trunnion 56 carried by the connecting rod 57, the ends of which are connected in any suitable well. known manner to the rocker arms 58 'arried by the rocker shafts 23.

From the foregoing it will be seen that the slide 38 is reciprocated the yoke at) will transmit motion to the connectingrod 5? and at right angles to the line of movement of the slide causing the rocker shafts to be oscillated for transmitting a reciprocating motion to the movable grate bars and 311. hingheads and the amount of this movement. will be controlled by the pitch of the yolze'which may be changed at the option of the operator, as will be obvious.

The n'iovenrnts of the piston 40 arcecontrolled by the entrance of steam into one or the other end of the cylinder e1 depending upon'the position of the piston, in said cyliir der, the steam in its passage to the cylinder fir a s t ble c rce e1 upp y r t ats? i an i'il

ing the. steam chest 59 through port 59 from where it will pass through one of the openings 60, 61 from said steam chest and through pipes-.60 and 61 to'the cylinder and d 1g the time the steam is entering one of aid openings tne exhaust steam will be lea ing the other opening and pass through the exhaust 62 to the atmosphere.

These openings and exhaust port are controlled by a valve 63 which is slidably mounted upon a piston rod (Si between two tappets (i and. its pistonrod is connected to a goven L at The governor piston is controlled by-a control valve 68 functioning within a valve housing 69 and having a valve stem 70 011 which are mounted tappets 71 coacting with a pivoted reversing lever T2 actuated by the movements of the ram 35 in any suitable or well known manner but as here shownthe means for actuating the reversing lever 72 includes a lever controllingrod 172 having one end lixcdl to the reversing lever 72 above the pivot point of the latter while the opposite end of said controlling rod runs iii-the inclined guide 173 on the side of the ram 35. lhe inward movement of the ram 9J5 will snde the guide 103v relative to, the

opened or closed by the movements ofthe control valve '68 which also controls the passageways 75, 76 leading from the valve chamber to the cylinder 67. The fluid entering the valve chain port 73 must be under pressure and although any suitable fluid may be used I have found that a free running 011 has many advantages,

some of which are its non-freezing and lubricating properties.

From the foregoing description it will be noted that the movements of the ram 35 will move the reversing l ver "2 into contact with first one and then the other of the tappets 71 thereby moving the control valve 68 back through the inlet.

and forth within the valve housing for openingand closing the a ternate branch ports leadii j from the inlet 73 and also alternately opening and closing the passageways 75, 76 so that the governor piston {56 will be actuated to move the valve63 hereinbe fore "stated. The valve 68 is of such. construction that when-1a communication is formed beween the inlet 78 and the passagewayfo a communication is also formed between the passageway 76 and the exhaust 69, thus allowing the fluid which has moved the governor piston to flow mto a suitable container ZUlCllllCE WlS'B when the :tluid enters the port 76 the valve 68 will be in position to permit the fluid in the cylinder 67 to pass through the port 5 into the exhaust.

\ The construction illustrated in Fig. 5 is particularly useful. in conjunction with extra long grate bars and provides I additional pushing means and in this form of the de -rice the imperforate grate bar 11. is held in. its set position by the lugs 17 engaging the outer partitions 18 and said imperforate grate bar is provided with a slot 78 intermediate its ends through which projects an extension 79 formed with the lower portion of the pushing head 19 having a pushing face 20 rising above the upper end of the imperforate grate bar, the said pushing head also having a recess orslot 18 for the reception of said upper end of the imperfora te grate bar.

This pushing head is actuated in the same manner as the others herein described, it

being provided with lugs 21 for coaction with the web 22v of the rocker shaft 28.

This form of the invention is preferably used in connection with the movable perfo rate grate bars 12 one of which is illustrated directly behind the imperforate grate bar and the movements of the pushing head will first advance the fuel of the fire bed along the upper portion ofthe grate bars as said fuel runs overthe pushing heads and upper ends of the grate bars and at some point further down the grate bars it w'll be given another propelling movement by the'entension 79 as the same is projected through the slot '78.

The gist of my invention is to providev pushing heads in conjunction With the grate bars of a stoker regardless of the particular construction of said grate bars and further to construct the pushing heads separate from said grate bars and therefore I do not wish to be limited to the exact details of construction as herein shown as these may be varied within the limits of the appended claims without departing from the spirit of my invention. 1

Having thus fully described my invention, what I claim as new and useful is 1. An underfeed stolzer comprising. in combination, a retort grate bars extending laterally from said retort, alternate ones of said grate bars being movable longitudinally and the others stationary, and reciprocating pi uing heads slidably mounted on the stationary grate bars.

2. An underfeed stoker comprising, in combination, a retort, grate bars extending laterally from saidretort, alternate ones of said grate bars being movable longitudinally and the ot iers having their outer ends an ehored to hold them stationary and pushing heads slidably mounted on the retort and on theinner ends of the stationary grate bars, said pushing heads supporting said inner ends of the stationarygrate bars.

3. An underfeed stolter comprising grate bars, pushing heads slidably mounted thereon, and means for reciprocating said push ing heads.

t. An underfeed stoker including grate bars and reciprocating pushing heads slicaoly mounted there-on.

5. In an underteed sto ter, aplurality of perforate grate bars, a plurality of stationary imperforate grate bars alternately located with respect to the perforate grate bars, and reciprocating pushing heads slidably mounted on'the stationary grate bars. 6. in an underfeed stolter, a plurality of longitudinally movable grate bars, a plurality of stationary grate bars alternately located with respect to the movable grate bars, and reciprocating pushing heads slidably mounted on the stationary grate bars.

7. In an underlfeed stoker, aplurality of movable grate bars, a plurality of stationary grate bars alternately located With respect to the movable grate bars, pushing heads slidably mounted on the stationary grate bars and having pushing faces projecting above and overlying the upper ends of the grate bars'on which they are mounted, and means for reciprocating said pushing heads.

8. In an underteed stoker, a plurality of lovable grate bars, a plurality of stationary ate bars alternately located with respect to the movable grate bars, pushing heads slidably mounted on the stationary grate bars and having pushing faces projecting above and overlying the upper ends of the grate bars on which they are mounted, and means for reciprocating the pushing heads and the movable grate bars in unison.

9. In an underi 'eed stoker, stationar grate bars and movable grate bars arranged in alternate relation, pushing heaos slidably mounted on the stationary grate bars, and means to reciprocate said pushing leads and the movable grate bars.

10. An underfeed 'stoker including grate bars having slots therethrough intermediate their ends, pushing heads slidably mounted on the grate bars, extensions carried by said pushing heads and projecting into the slots through said grate bars, and means for reciprocating said pushing heads. Y

11.. An underteed stoker including a plurality of longitudinally movable perforate grate bars, a plurality of stationary impertorate grate bars alternately located with respect to the perforate grate bars and having slots therethrough intermediate their ends, pushing heads slidably mounted on the impertorate stationary grate bars, e2;- tensions carried by said pushing heads and projecting through the slots, and means for reciprocating the movable grate bars and said pushing heads. I

12. An underfeed stoher comprising, in combination, a retort, grate bars located on both sides oi said retort, alternate ones of said grate bars being movable lon itudinally and the others stationary, pushing heads slidably mounted on the stationary grate bars at the retort ends, pushers in the retort, and a mechanism for reciprocating the retort pushers, the pushing heads and the movable grate bars.

In testimony whereof, atlixed my signature.

EDl VARD J. HART.

l have hereunto 

